Asking a seller or dealer about oil changes is practically meaningless, as most sellers will tell you what you want to hear and dealers won’t know.
First things first, the car should be cold unless there is a good reason why it shouldn’t be (They met you in a parking lot away from home). Check under the oil cap for a milky substance. All white can mean some condensation is there, usually from an idle vehicle and that’s not all that bad. But milky (Like chocolate milky) means water or coolant in the oil, and that means it’s time to walk away.
You still want to check the oil, just in case, but most people will get an oil change when they go to sell a car, and when they do they get fresh clean oil that isn’t going to tell you the full story.